Evacuation from coaches
Although serious crashes and fire incidents involving buses and coaches are rare, they can have desastrous outcomes when they occur due to the large number of passengers transported in a single vehicle. The German Insurers Accident Research contracted a research project to Trier University in order to investigate into the possibilities to enhance and speed up the evacuation process in coaches. The focus was on accident scenarios, particularly those in which the coach tipped over onto its side.
After an analysis of crashes in Europe during recent years and data from the German Insurers Accident Database, it was found that a considerable proportion of involved coaches ended up on the right vehicle side, making their regular doors inoperable or inaccessible.
Several trials were run with nearly 40 participants, each, to explore different aspects of evacuation under controlled conditions in a full-scale coach as well as in a mock-up, representing a typical center section of a coach.
As passengers are required to use seat belts during travel, different belt systems were compared regarding the ease of unbuckling them by the user. 3-point safety belts could be opened easier and quicker by the participants in a coach tilted sideways by 30°.
In the next step, the movement of passengers inside the coach was investigated with the vehicle tilted by 30° and by 90°. Participants were asked to walk from the front to the rear door to test whether they would be able to move safely through the inclined center gangway (in case of 30° inclination) and on top of the side window glazing (in case of the 90° turned vehicle). In addition, they were asked to indicate the nearest and most suitable emergency exit. Depending on the coaches‘ position, different exits were preferred. However, these were not necessarily the closest and most suitable ones. For instance, the windscreen at the vehicle’s front was indicated by many participants. However, it cannot be opened from the inside without heavy tools. In contrast, the window at the rear of the coach was identified only by a few participants, although it is designed as an emergency exit.
Finally, the time used to exit through a roof hatch with the coach lying on its side was determined under laboratory conditions. In this situation, a roof hatch of rectangular shape that was mounted transversely across the roof proved far easier to step through than a hatch of the same shape and size, but installed in the longitudinal direction of the vehicle.
In essence, the project identified a number of weak points in the typical general layout of a coach or bus when quick and safe evacuation of their passengers is required. Among other improvements, the installation of 3-point seat belts and – in the midterm – windscreens that are also designed to be used as an emergency exit are some of the recommendations for the industry.